Variable delta is the variant of concern (VOC) of SARS-CoV-2, which was first identified in India, in Maharashtra, at the end of 2020. Inphylogenetic tree of SARS-CoV-2, Belongs to branch B.1.617.2. The latter also includes two “sub-variables”: the Delta Plus variant (B.1.617 + AY1), and B.1.617 + AY2, which was discovered in the United States.

The alternate delta It is characterized by several mutations throughout its structure, but the most important one is found in the S protein: L19R, a delete At position 157/158, L452R, T478K, all are in the N-terminal domain; and D950N in the receptor binding domain (RBD). The L452K mutation is looked for in screening tests. It is necessary to confirm the existence of a file alternate delta in a sample.

This variant is 40 to 60% more infectious than the other variants in the circulation and is shown to be less sensitive to neutralizing antibodies. Scientists from the Pasteur Institute shed light on this that Serum Of convalescent patients it is 4 times less effective against the delta variant, compared to the alpha variant. Also, a single dose of the vaccine is not enough to inhibit Repetition from the delta variable. in the end From the second dose, 95% of the individuals tested by the same scientists developed a neutralizing response against alternate delta But it is about 3 to 5 times less severe.